In a power system, as a method for adjusting power demand and supply, a method has been adopted, which mainly uses the output control function of thermal power generation equipment of a thermal electric power plant, and properly combines an output adjustment function of pumping-up hydraulic power generation.
However, if renewable power sources, which are typified by photovoltaic power generation and wind power generation where the power generation amount depends on weather conditions, are connected to the a power system as distributed power sources, there may arise the situation in which output variations of the distributed power sources cause a greater loss of balance between power demand and supply than in the related art. As a result, in order to compensate for a variation in the balance of power demand and supply that is caused by the distributed power sources, the only method that is likely to be insufficient is the method that adjusts the balance of power demand and supply by mainly using thermal power generation equipment, as in the related art. Therefore, in addition to the related art, a more effective technology for adjusting the balance between power supply and demand is needed.
As one technology that can address this need to adjust the power demand and supply balance, there is a promising technology that uses distributed energy storage (hereinafter, an energy storage will be called “ES”) such as “a storage battery” that interconnects to the distribution network of a power system, and is expected to come into widespread use from now on.
Patent Literature 1 describes a power system control method that adjusts power demand and supply by using a secondary battery (ES) in a consumer side.
In the power system control method described in Patent Literature 1, a power system control device acquires an amount of charge in a secondary battery, and further acquires a schedule of power supply to a power system that is generated based on a power demand forecast from a central power supply instruction office or the like. The power system control device determines an operation schedule of the secondary battery based on the amount of charge in the secondary battery and the power supply schedule.
When the power system control device determines the operation schedule of the secondary battery, the power system control device transmits the operation schedule to a secondary battery control system that controls the operation of the secondary battery.
When the secondary battery control system receives the operation schedule from the power system control device, the secondary battery control system controls charge and discharge of the secondary battery in accordance with the operation schedule, irrespective of the actual state of the power system.
Furthermore, Patent Literature 2 describes a system in which a central controller acquires state of charge information of a plurality of battery cells sampled at the same point of time via a local monitor and an upper controller.